In the existing EPC (Evolved Packet Core) architecture, a UE (User Equipment) may be connected to the EPC through a non-3GPP (3rd Generation Partnership Project) access network. Multiple PDN (Packet Data Network) connections exist between a non-3GPP access network and a PGW (PDN Gateway, packet data network gateway). Accordingly, multiple gateway control sessions will be established between the non-3GPP access network and a PCRF (Policy Control and Charging Rules Function), and multiple IP-CAN (IP Connectivity Access Network) sessions will be established between the PGW and the PCRF. In order that the PCRF may provide correct QoS (Quality of Service) rules to the non-3GPP access network, the PCRF needs to associate corresponding gateway control sessions and IP-CAN sessions.
Currently, the procedure for associating, by the PCRF, gateway control sessions and IP-CAN sessions may be implemented by using the following methods:
1) Match an IP-CAN session and a gateway control session according to an HoA address (Home Address) or a CoA address (Care-of Address) provided by the IP-CAN session and IP addresses provided by the gateway control session. Specifically, if there is an IP address that is the same as the HoA address or CoA address among at least one IP address provided by the gateway control session, the PCRF may associate the IP-CAN session and the gateway control session according to the same IP address.
2) Match an IP-CAN session and a gateway control session according to PDN identities and subscriber identities in the IP-CAN session and the gateway control session. Specifically, if the IP-CAN session and the gateway control session carry the same PDN identities and subscriber identities, the PCRF may associate the IP-CAN session and the gateway control session.
When an EPC is connected through an untrusted non-3GPP access network, to ensure security of the EPC, a security gateway, for example, ePDG (evolved Packet Data Gateway) needs to be established between the untrusted non-3GPP access network and the EPC; the untrusted non-3GPP access network allocates a local address IP_Local to a UE, and then the UE uses IP_LOCAL to establish a secure tunnel with the ePDG. The gateway control session may be initiated by the untrusted non-3GPP access network, or may be initiated by the ePDG.
When implementing association of the gateway control session and IP-CAN session, the inventor finds at least the following problem in the prior art:
A gateway control session initiated by an untrusted non-3GPP access network cannot be associated with an IP-CAN session.
The gateway control session and the IP-CAN session involved in the preceding description are both used to acquire policy control rules. Therefore, the gateway control session and the IP-CAN session should belong to the policy control sessions. That is, when a policy control session initiated by an untrusted non-3GPP access network lacks information such as an HoA/CoA address and a PDN identity, it is hard to be associated with other policy control sessions.